Can Fetal Movements Predict a Baby’s Sex or Temperament?

by Alice Callahan on October 30, 2014

I’m now 31 weeks pregnant. The weeks are flying by, and for the most part, I’m relishing all the physical changes in my body and the preparations for this baby. We waited a long time for this pregnancy, and it will probably be my last. I curl around my belly at night and think about the baby growing inside me. I wonder about the person that he or she will become and how our little family will adapt to welcome a second child. (We’ve chosen not to learn the sex of this baby until its birth.)

When I was pregnant with Cee and about to become a mom for the first time, I thought a lot about what kind of mother I would be and how this big life transition might alter my identity, my career path, my marriage, and my daily life. The baby-to-be was kind of a vague amalgamation of all the babies I’d known.

This time around, having been around many more babies, I recognize the individuals that babies are from the first days of life – and even in utero – and I spend a lot more time wondering about this baby’s temperament and personality. Introverted and contemplative, like Cee? Or totally different?

Filling me with wonder, this baby moves around in utero a lot, and this feels very different from my experience carrying Cee. I didn’t feel movement from Cee until around 23 weeks, but I began to feel this baby move at 16 weeks. And this baby continues to be very active, more than I remember with Cee, especially making big, dramatic movements in the evening hours but also having significant activity bouts throughout the day (and sometimes in the middle of the night, of course).

Because we don’t know the sex of this baby, I’m often asked if I have any predictions on that front. How would I know, I think? I don’t feel like I have any kind of gut instinct for this kind of thing, and I don’t buy into any of the old wives tails. But if I’m pushed to make a guess, I guess that this baby is a boy. And when I ask myself why that is, it comes down to this observation about more fetal movements. This baby feels different from Cee, and my brain makes a jump to sex as a possible explanation. And then I stop, remind myself that I’m perpetuating a total gender stereotype, and feel embarrassed.

One day, I repeated all of this to a friend as we walked together (complete with an apology for the gender stereotype), with Cee riding her bike within hearing distance. A couple of weeks later, my mom was talking to Cee on the phone and asked her if she thought the baby would be a boy or a girl. Cee answered in what seemed like a verbatim copy of my own explanation: “Well, Mom thinks that it’s a boy, because the baby moves around a lot inside of her, and I didn’t move very much.” Yikes. From now on, I’m keeping my mouth shut. And for the record, Cee is really hoping for a little sister.

All of this left me wondering if fetal movements can actually predict anything about the baby, whether sex or temperament, in postnatal life. I happened to be corresponding with Jena Pincott, author of Do Chocolate Lovers Have Sweeter Babies?, a few weeks ago, and I asked her if she knew of any research on this. She wrote back, “As for ‘in utero’ forecasts, my prediction is that your 2015 is going to be very, very busy!” and sent me a few research articles. I dug around and found quite a few more studies of this question. Finally, I could stop speculating and start talking science! Here’s what I found:

How is this question studied?

Most studies use ultrasound or a Doppler transducer placed on the mother’s belly to measure fetal movements. Most are conducted over a period of about an hour, during which the moms are asked to rest, and the best studies take several of these measurements over the course of the pregnancy. Studies of postnatal temperament then use standardized behavioral observations or questionnaires to describe aspects of the baby’s behavior.

Is it true that some fetuses are more active than others?

I wondered if my perception that I was carrying a more active fetus is this pregnancy was really true or if it was influenced by other factors? Women in their first pregnancy usually notice fetal movements a few weeks later than those in subsequent pregnancies, but it isn’t clear if number of pregnancies affects detection of fetal movements later in gestation.4,5 Other factors, like position of the placenta and maternal body weight, may play a role.6,5 Although these may add variation to perceptions of fetal movement, studies using objective measures of fetal movements (like ultrasound or Doppler transducers) do consistently find that some fetuses are more active than others. That is, when researchers measure fetal activity at several time points during pregnancy, they find that fetuses that are very active at one time point continueto beveryactive at later time points.3,7–9 However, I recognize that I’ve personally only felt fetal movements in two pregnancies, and my perception of these movements is probably not entirely objective.

Can fetal activity help us to predict a baby’s sex?

Most studies have found that fetal movements aren’t a reliable predictor of infant sex. For example, two longitudinal studies (measuring fetal activity at several time points during pregnancy), one conducted in both Maryland and Peru and the other from the Netherlands, found no difference in fetal activity patterns between males and females.1,2 As I’d suspected, basing my prediction about my baby’s sex on fetal activity was not evidence-based. It is an understandable mistake, however, because studies have found that, on average, boys are more active than girls in toddlerhood. For example, this study found no difference in activity level between male and female fetuses or as newborns but did find that boys were more active at 1 year of age and tended to be more active at 2 years.3 However, this difference doesn’t seem to trace back to fetal life and may be shaped at least in part by cultural expectations.

Can fetal activity predict a baby’s temperament?

Yes! All of those kicks at my uterus may really have a story to tell about the baby inside of me. A link between fetal activity and postnatal temperament has been observed in multiple studies. Here are a few of the most interesting ones:

More fetal movements might mean that a baby will cry more. A U.K. study asked pregnant moms to keep 1-hour diaries of fetal movements, classifying each one as weak or strong, in the morning and evening for 3 days at 37 weeks of pregnancy. The moms then completed 24-hour diaries of their babies’ behavior at 1, 6, and 12 weeks postpartum. Strong fetal movements didn’t correlate to later baby behavior, but the number of weak movements did. Fetuses that had more of those weak movements in pregnancy (versus those that had fewer weak movements) ended up fussing and crying more in infancy. On the bright side, fetal movements weren’t correlated to sleeping patterns or feeding behavior.10

More fetal movements might indicate that a baby is more likely to be more active, unadaptable, and unpredictable. Dr. Janet DiPietro of Johns Hopkins has been studying fetal development for more than 20 years, including several studies of this question of what fetal activity can tell us about our children before their birth. One of the first, published in 1996, found that more active fetuses became babies that were “more difficult, unpredictable, unadaptable, and active,” based on maternal questionnaires at 3 and 6 months of age.

Babies that move more in pregnancy might be less easily frustrated at 1 year and more independent at 2 years. Another study from Janet DiPietro’s lab included behavioral assessments at 1 and 2 years of age. In one test, the 1-year-old babies watched as a fun-looking toy was placed behind a Plexiglass barrier, out of their reach, and the researchers noted how distressed they were by this set-up (banging on the glass, etc. vs. moving on to something else). In another, the babies were simply strapped into a car seat, a familiar scenario that most of us know can produce frustration in a baby. At age 2, the children were observed playing in their homes while the mothers were instructed to sit close by but to act too busy to interact with their toddlers. There was a correlation between having more fetal activity and being less upset about the 1-year-old tests and playing more independently of mom at age 2. There was also an interesting association with sex in this study. At age 1, boys who were more active in utero were also more active toddlers; however, girls who were more active in utero were the opposite – less active as toddlers.

I think this research is really interesting, but I also am careful to not try to apply it too literally to this child that I haven’t yet had a chance to meet. These studies are specifically trying to separate out fetal movements from many other sources of variation. They look at many babies and use mathematical models to identify patterns in the group, but they really can’t tell us anything about our own particular babies. And I want to be careful not to project my expectations about temperament on my baby or for this to affect how I treat him or her. I’ll do my best to let my baby tell me who he or she is. But in the meantime, it is fun to feel those kicks and wonder about this child. And it doesn’t hurt to be mentally prepared for a baby that might cry a little more than average.

While perusing the research on fetal movements, I also learned a few other fun facts:

It’s normal to feel stronger fetal movements in the evening hours. In one study, moms reported feeling an average of 4 strong movements per hour in the morning and 12 per hour in the evening.10

Fetuses that were observed to be sucking their right thumb during ultrasounds were more likely to be right-handed at 10-12 years of age.11

Maternal cortisol levels during pregnancy were associated with more fetal movements and greater amplitude of movements during the third trimester.12 (But don’t stress about this! I’m not. See above for my cautions about applying this research directly to our own pregnancies.)

When pregnant moms participated in a guided imagery relaxation exercise, which resulted in physiological signs of relaxation in the moms (lower heart rate, respiration rate, and skin conductance), fetal movements also decreased.13

Did you notice any correlations between fetal activity and your children’s temperament? We’ve talked about the data, and anecdotes are welcome!

No temperament evidence yet – since this one is still in-utero. However, we were suspicious early on that this one was going to be male (and have now had both Maternit21 and an anatomy ultrasound that agree on male) because it was pretty obvious by my behavior that the set of hormones was really different than with my daughter.

I meant to look for research on that but didn’t get around to it other than learning the main period of the hormonal differences to form the genitals is about 9-20 weeks, and I definitely do agree with that time frame.

I was very foggy brained during this period with my older child (female) and was a lot more overtly interested in my husband during the same time with this baby (even when I was annoyed with him for other things, which was really unusual for me, so we made lots of welcome to testosterone drive jokes).

Hi what are the differences of being pregnant with a boy or a girl I have no idea I know with my first two pregnancies I was lazy and laid back and this third pregnancy is different I clean more don’t cry as much and don’t really have to up to have intercourse with my husband but my ultrasound said I was having another boy and it just doesn’t feel right or true for that matter how would I know? Can you help me please?

In all of my pregnancies, the kids were active, and they remain so out of utero! I have a girl and two boys.

From what you said, I wonder if your placenta with Cee was anterior because you didn’t feel movement until the 2nd trimester. Also, with subsequent pregnancies, the uterus is a bit larger, so often moms feel the fetus earlier.

Fascinating studies, thanks for sharing! My son is 2.5 now, and is one active guy. In utero he was quite active and would stick his feet up in my ribs. When I was pushing during labor, his feet were up there as if he was trying to launch himself out! As a baby he was such a kicker, often when excited or happy. I notice now he still likes to swing and tap and dance with his feet. When we snuggle in bed he likes to put his feet between my legs. Definitely something there about his interest in movement.

Sounds like an interesting question about temperament, but in my opinion temperament is strongly influenced by the mother. Excitable moms will regard their kids as excitable; calm moms will think their kids are calm.

This was a great read! I’ve been wondering this exact thing as I am having my first baby and have felt a lot of movement since 16 weeks (even stopping myself when I thought ‘boy’ and saying “or just an active girl!” haha). I agree with not worrying too much before actually meeting the babe, but it helps to be a bit prepared 🙂

So interesting! I have two girls and a boy, and both my girls moved around tons in utero while my boy barely moved at all. Many a day found me chugging orange juice and laying upside down on the couch trying to see if he was still alive in there. Up until about 12 months he was a much calmer and easy-going baby than my girls were. Fast forward a few months though and he’s just as much of a rambunctious little toddler! Thanks for sharing all the links!

My daughter (now 11 months) was quite active in utero—she moved repeatedly from breech to vertex between weeks 35 and 39, which is so unusual, especially as she was normal-sized, my fluid levels were normal, etc. She was born head down but sunny-side up and has been a very alert and active baby ever since (most common comment when she was a newborn: Wow! I’ve never seen a newborn keep her eyes open so much…yupppp! blessing/curse). I worried so much about her frequent flipping in utero, as breech can sometimes indicate problems. Now I think it was my first indication of her personality.

Thanks so much for looking into this! About a year ago I tried to do the same thing because I had noticed that my (now) 16-month-old son was FAR more restless, irritable, demanding, and difficult to settle than my first son had been. I remember thinking with my first that babies were not so difficult to get to sleep and feed and so forth that everyone made them out to be, and that perhaps it was just parenting style that was causing all the ruckus. Boy was I wrong! I have raised these two exactly the same, but now that irritable baby has grown up into a constantly cranky toddler who exhausts me every minute he is awake. We call him “Stitch”, as in Lilo and Stitch, because he is an adorable but destructive force that never stops moving. The reason I had been looking up fetal movements and temperament (unsuccessfully) was because while I was pregnant with him I had noticed the same. Even a Dr during an ultrasound noticed that he was turning somersaults and carrying on and said “Wow, he is really active!”. For months we tried to find a name we liked for him that literally meant “restless” because it just felt like that was who he was. We never did succeed in that regard, but Stitch as a nickname seems to cover it!

My daughter was very active–I first felt movements around 16 weeks, and whenever I had an ultrasound, she wouldn’t stop moving. At one, the technician had to take several measurements of her head because she kept shifting. She had a habit of what felt like her scratching her fingers against the area of the placenta nearest my hips, which has continued into a self-soothing action now: she kneads her fingers into the the arm or neck of whoever’s holding her if she’s sleepy or upset.

And at 14 months, she’s still quite active. The fidgetiness she had in utero seems to have translated into a child who is extremely curious about her surroundings and loves to walk and climb. However, she’s proved to be fairly adaptable to new circumstances. Camping and moving were both things she’s taken in stride. Sometimes she surprises me by crying at the littlest things (she was scared of trees for a few months, which made no sense at all–now she points at them whenever we’re outside), and then not at all at bigger things (she just watched calmly as the nurse gave her the flu shot yesterday).

I kept a movement journal of my daughter in the womb to see if it coincided with her sleep patterns after she was born (it was roughly the same for her first month of life). I have to tell you my daughter was a very BUSY baby inutero and for hours at a time in the evening (I have videos to prove it!). At certain times of the day I would have 4+ movements in one minute (literally). She is currently 5 months and busy as a bee. She is a great eater and sleeper but when she is awake she is VERY alert, very interested, babbling, imitating mouth movements, rolling over, trying to crawl and likes to be attended to all the time (I wear her a lot).She is really just amazing. So far one thing is evident – she is clearly extroverted (unlike her mommy). Great post!

Great post! It took me right back to my pregnancy days, monitoring all those kicks and hiccups. I’m glad you’re savoring this time! I only have one child and so I can’t compare pregnancies, but I thought my son moved a fair amount. Maybe he was relatively active because he definitely cried a lot. Also, he is 2.5 now, and is he ever on the move! When he was almost 2, he once ran circles through our living room, dining room, and kitchen for 20 min. straight. Luckily there are periods when he’ll mellow out play independently, but when he’s on, he’s ON. I do not recall my younger female cousins being this way when they were toddlers. But memory is tricky and gender is in the eye of the beholder, too; maybe when I see my son bouncing off the walls, I think “what a boy,” and just didn’t register and don’t remember the times when my girl cousins were rambunctious.

Thanks for another great post, Alice. Both my kids were pretty intense wigglers in the womb. One boy and one girl. I’ve been wondering about other indicators of sex. For example, with both my kids I had several other women correctly guess the gender of the baby, and when I asked them how they knew, they’d always comment on how I carried the baby. Does anyone know of studies that have been done on this? Is there really a way to tell, or did these women just happen to be lucky?

My daughter (now 5) was incredibly active in utero, all day and all night. The only thing that would calm her down has hot spicy food. She is a relatively calm child, happily playing by herself for several hours. But she does have periods of intense activity when ooutside. She is high emotion, but she also loves new experiences and is quite adaptable. She is a fabulous sleeper, often asking to go to bed. She slept through the night at six weeks. The only thing I would correlate to her in utero behavior is that she still loves hot spicy food.
I wonder if there is a difference in the results of the studies if you broke out first children from all the rest (experienced moms vs new moms).

Delurking to say: loved this post! I am also expecting my second child and could identify with a lot of what you are saying –both on the focus on my attention and on not jumping to conclusions about sex based on preconceptions.

Nothing was more amazing was when I was pregnant with my now 6yr old twins. All the births of my boys where amazing but with my twins I felt to little lives moving inside and they had their own personalities. Baby A and Baby B it is indescribable.

My son was extremely, and I mean extremely, active during pregnancy, and he has been extremely active since he was born. Even as an infant his legs were always going and now that he is two he is super active and very busy!!

You should check out The Child Whisperer by Carol Tuttle. She talks about children’s different temperaments and has parenting tips based on your child’s nature. Movement is totally a predictor! It’s a really useful book, and goes along with what was shared here.

I’d love to know more about this in twin studies. At 11 weeks we have one who each visit bounces off the proverbial walls while the other is cuddled up. Who knows how this will change as they grow and lose space. A plus side is that we have sonograms every couple of weeks to check in on them.

If you went through that much trouble because you’re wondering about the sex of the baby, why not just find out and give your mind a break? I appreciate the information but it sounds like a lot of work for someone who doesn’t want to know.

Ha! Well, I guess we’re all different, huh? I was curious and interested in the science I suppose. The baby’s sex and personality were still most definitely a surprise at his birth, as I didn’t claim that this information could tell us anything with certainty.

Great read. My 18 month old moved so much, every little stimulation set her off. It was crazy! I never imagined how much that would transfer to her personality out of the womb. She can’t ever seem
To sit down. She always has to be up and running around, doing something. 😅 It really does make sense.

I’m currently 34 weeks, doctors say I’m having a girl. This is is my first and I can remember being almost 20 weeks and feeling her. She’s was very active then and still is, I wonder if that means she’s gonna be hyper out side the utero. The main reason why I came across ed this article, is that I’m keeping count of her movements, the most she moves is 29times in a min. Is that alot? Is that healthy? Does anyone know?@

hi Alice, I am in exactly the same situation you were with your second! And I am wondering how things panned out for you 🙂 How would you describe the temperament of your number two, now that you would have had time to observe them? cheers!

Great article! My first girl was very active in my womb and always had a high heart rate of 160. She was a veery fussy baby who cried many hours of the day and fought sleeping. Now she is 3 and in comparison to others a really easy toddler. She is still sensitive and cries a lot but she laughs a lot as well and enjoys life. My second girl always had a low heart rate 130-140 and was super calm. Soo easy as a baby. Now she is over one. She is a little bit more fearful than my first. She doesn’t nearly cry as much as my older but she doesn’t laugh as much either. Still easy though. Now I am pregnant with my third girl. High heart rate again! I am just hoping and praying she won’t be as restless as my first. That was a super hard first year. We shall see 🙂 3 girls should be fun…my little princess farm 😀

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Welcome! I'm the author of The Science of Mom: A Research-Based Guide to Your Baby's First Year, published by Johns Hopkins University Press in 2015. I write about science, health, parenting, and nutrition here and for other print and online outlets.
Find more about me at my website: https://alicecallahanphd.com/

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